Optoelectronic modules that have shielding to reduce light leakage or stray light, and fabrication methods for such modules

ABSTRACT

Various optoelectronic modules are described that include an optoelectronic device (e.g., a light emitting or light detecting element) and a transparent cover. Non-transparent material is provided on the sidewalls of the transparent cover, which, in some implementations, can help reduce light leakage from the sides of the transparent cover or can help prevent stray light from entering the module. Fabrication techniques for making the modules also are described.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. application Ser. No.15/367,257, filed on Dec. 2, 2016, which is a continuation of U.S.application Ser. No. 14/339,657, filed on Jul. 24, 2014, which claimsthe benefit of priority U.S. Application No. 61/915,193, filed on Dec.12, 2013 and U.S. Application No. 61/859,828, filed on Jul. 30, 2013.The disclosure of the prior applications is incorporated herein byreference.

FIELD OF THE DISCLOSURE

This disclosure relates to optoelectronic modules have shielding to helpreduce light leakage or stray light, and fabrication methods for suchmodules.

BACKGROUND

Smartphones and other devices sometimes include miniaturizedoptoelectronic modules such as light modules, sensors or cameras. Lightmodules can include a light emitting element such as a light emittingdiode (LED), an infra-red (IR) LED, an organic LED (OLED), an infra-red(IR) laser or a vertical cavity surface emitting laser (VCSEL) thatemits light through a lens to outside the device. Other modules caninclude a light detecting element. For example, CMOS and CCD imagesensors can be used in primary or front facing cameras. Likewise,proximity sensors and ambient light sensors can include a light sensingelement such as a photodiode. The light emitting and light detectingmodules as well as cameras can be used in various combinations. Thus,for example, a light module such as a flash module can be used incombination with a camera that has an imaging sensor. Light emittingmodules in combination with light detecting modules also can be used forother applications such as gesture recognition or IR illumination.

As illustrated in FIG. 1, one challenge when integrating anoptoelectronic module 10 into a device such as a smartphone is how toreduce light leakage 14 from the light source 16 in the light module, orhow to prevent incoming stray light from impinging, for example, in thecase of sensors or cameras. Preferably, light emitted from light source16 (or light to be detected by a sensor in the module) should passthrough lens 12 and exit (or enter) directly through the transparentcover 18 of the module 10. However, in some cases, some of the light 14exits (or enters) the sides of transparent cover 18, which can beundesirable.

SUMMARY

The present disclosure describes various optoelectronic modules thatinclude an optoelectronic device (e.g., a light emitting or lightdetecting element) and a transparent cover. Non-transparent material isprovided on the exterior sidewalls of the transparent cover, which, insome implementations, can help reduce light leakage from the sides ofthe transparent cover or can help prevent stray light from entering themodule.

In addition, various techniques are described for fabricating themodules. In some implementations, the modules can be fabricated in awafer-scale process. Such processes allow many modules to bemanufactured at the same time. In some implementations, various elements(e.g., an optical element such as a lens, an optical filter, or a focallength correction layer; or a spacer) can be formed directly on one sideor both sides of the transparent wafer using one or more vacuuminjection and/or replication tools.

For example, in one aspect, an optoelectronic module includes anoptoelectronic device mounted on a substrate, and a transparent coverheld at a distance from the substrate by a spacer. The spacer iscomposed of a material that is non-transparent to light emitted by ordetectable by the optoelectronic device. Sidewalls of the transparentcover are covered by a material that is non-transparent to light emittedby or detectable by the optoelectronic device.

Some implementations include one or more of the following features. Forexample, the module also can include an optical element (e.g., a lens,an optical filter (e.g., a dielectric band-pass filter) and/or a focallength correction layer on a surface of the transparent cover). Thenon-transparent material covering the sidewalls of the transparent covercan be, for example, the same material of which the spacer is composed.In some cases, the non-transparent material covering the sidewalls ofthe transparent cover is a polymer material (e.g., epoxy, acrylate,polyurethane, or silicone) containing a non-transparent filler (e.g.,carbon black, pigment, or dye). The transparent cover may besubstantially parallel to the plane of the substrate or tilted at anangle with respect to the plane of the substrate.

In another aspect, a method of fabricating optoelectronic modulesincludes providing, on a support surface, a plurality of singulatedtransparent substrates separated laterally from one another. A vacuuminjection technique is used to cover sidewalls of each of the singulatedtransparent substrates with a non-transparent material, and spacerelements are formed that project away from the support surface. In somecases, the method also includes forming or applying a respective opticalelement (e.g., a lens, an optical filter (e.g., a dielectric band-passfilter) and/or a focal length correction layer on a surface of thetransparent cover) on a surface of each of the singulated transparentsubstrates.

Some implementations include one or more of the following features. Forexample, the spacer elements can be formed as part of the same vacuuminjection technique used to cover the sidewalls of the singulatedtransparent substrates with a non-transparent material. In some cases,the same combined replication and vacuum injection tool(s) is used forthe replication technique and for the vacuum injection technique.

In some implementations, the method includes using a first vacuuminjection tool to cover the sidewalls of the transparent substrates witha non-transparent material and to form the spacer elements on a firstside of a plane in which the transparent substrates are located during afirst vacuum injection process, and using a second combined replicationand vacuum injection tool to form the optical elements on a second sideof the plane during a replication process and to form projections on thesecond side of the plane during a second vacuum injection process. Theprojections can serve, for example, as non-transparent baffles and/oralignment features for the optoelectronic modules.

According to another aspect, a method of fabricating optoelectronicmodules includes providing a plurality of singulated transparentsubstrates within openings of a non-transparent wafer disposed on asupport surface. The transparent substrates and the non-transparentwafer are in a plane, and the support surface has openings adjacent afirst side of the plane. The method includes forming a respectiveoptical element on each of the transparent substrates on a second sideof the plane using a replication technique, filling the openings in thesupport surface with a first non-transparent material using a firstvacuum injection process, and forming non-transparent spacer elements onthe second side of the plane using a second vacuum injection process.

According to yet a further aspect, a method of fabricatingoptoelectronic modules includes providing a wafer that has a pluralityof transparent portions laterally spaced from one another. Each of thetransparent portions is surrounded laterally by non-transparentmaterial, and the wafer is in a plane and is disposed on a supportsurface that has openings adjacent a first side of the plane. The methodincludes providing a combined replication and vacuum injection tool on asecond side of the plane. A respective optical element is formed on eachof the transparent substrates on the second side of the plane by areplication technique using the combined replication and vacuuminjection tool. The openings in the support surface are filled with afirst non-transparent material, and spacer elements composed of thenon-transparent material are formed on the second side of the plane by avacuum injection process using the combined replication and vacuuminjection tool.

According to another aspect, an optoelectronic module includes anoptoelectronic device mounted on a substrate, a transparent coverseparated from the substrate by a spacer, and an optical elementattached to the transparent cover. Sidewalls of the transparent coverare covered by a first material that is non-transparent to light emittedby or detectable by the optoelectronic device, and the firstnon-transparent material is surrounded laterally by a second differentnon-transparent material. In some implementations, the firstnon-transparent material is a polymer material (e.g., epoxy, acrylate,polyurethane, or silicone) containing a non-transparent filler (e.g.,carbon black, pigment, or dye), and the second non-transparent materialis a glass-reinforced epoxy laminate material. Other non-transparentmaterials can be used as well.

In accordance with yet another aspect, a method of fabricatingoptoelectronic modules includes providing a substrate wafer thatcomprises a metal frame and a molded cavity, wherein portions of themetal frame are encapsulated laterally by the molded cavity, and themetal frame has optoelectronic devices mounted thereon and separatedlaterally from one another. The method includes providing aspacer/optics structure that includes singulated transparent substratesseparated laterally from one another, the spacer/optics structureincluding a spacer element that projects away from the transparentsubstrates, wherein sidewalls of each of the transparent substrates isencapsulated laterally by a non-transparent material. An end of thespacer element is attached to the molded cavity to form a stack.

In some instances, a module may include an optics assembly on theobject-side of the transparent cover. The optics assembly can include,for example, one or more lenses (e.g., a vertical stack of injectionmolded lenses).

Other aspects, features and advantages will be readily apparent from thefollowing detailed description, the accompanying drawings and theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of an optoelectronic module.

FIGS. 2A-2H show examples of optoelectronic modules.

FIGS. 3A-3E illustrate steps in a method of fabricating optoelectronicmodules using singulated transparent substrates.

FIGS. 4A-4C illustrate steps in a method of fabricating optoelectronicmodules having tilted transparent substrates.

FIGS. 5A-5E illustrate steps in another method of fabricatingoptoelectronic modules having tilted transparent substrates.

FIGS. 6A-6C illustrate steps in a yet a further method of fabricatingoptoelectronic modules having tilted transparent substrates.

FIGS. 7A-7E illustrate steps in another method of fabricatingoptoelectronic modules using singulated transparent substrates.

FIGS. 8A-8D illustrate steps in yet a further method of fabricatingoptoelectronic modules using singulated transparent substrates.

FIGS. 9A-9D illustrate steps in another method of fabricatingoptoelectronic modules using singulated transparent substrates.

FIGS. 10A-10B illustrate steps in a further method of fabricatingoptoelectronic modules using singulated transparent substrates.

FIGS. 11A-11B illustrate steps in yet a further method of fabricatingoptoelectronic modules using singulated transparent substrates.

FIGS. 12A-12D illustrate steps in yet a further method of fabricatingoptoelectronic modules using singulated transparent substrates.

FIGS. 13A-13E illustrate steps for fabrication of proximity sensormodules that include both a light emitting element and a light detectingelement in adjacent channels.

FIGS. 14A-14D illustrate steps in a method of fabricating optoelectronicmodules using a wafer with transparent portions surrounded bynon-transparent material.

FIGS. 15A-15F illustrate steps in accordance with another method offabricating optoelectronic modules using transmissive substrates thatspan across multiple optoelectronic devices.

FIG. 16 is an example of a module obtained by the process of FIGS.15A-15F.

FIGS. 17A-17F illustrate steps in accordance with yet another method offabricating optoelectronic modules using transmissive substrates thatspan across multiple optoelectronic devices.

FIGS. 18A-18B illustrate additional steps for fabricating optoelectronicmodules according to some implementations.

FIG. 19 illustrates a first example of separating the structure of FIG.18B.

FIG. 20 is an example of a module obtained by the separating of FIG. 19.

FIG. 21 illustrates a first example of separating the structure of FIG.18B.

FIG. 22 is an example of a module obtained by the separating of FIG. 21.

FIGS. 23A-23C are further examples of modules.

FIGS. 24A and 24B illustrate steps in a method of fabricatingoptoelectronic modules.

FIGS. 25A-25G are further examples of modules.

DETAILED DESCRIPTION

The present disclosure describes various techniques for fabricatingoptoelectronic modules that include non-transparent material on theexterior sidewalls of the transparent cover. An example of such a moduleis illustrated in FIG. 2A, which shows a module 20 including anoptoelectronic device 22 mounted on a printed circuit board (PCB) orother substrate 24. Examples of the optoelectronic device 22 include alight emitting element (e.g a LED, an IR LED, an OLED, an IR laser or aVCSEL) or a light detecting element (e.g., a photodiode or other lightsensor).

A transparent cover 26 composed, for example, of glass, sapphire or apolymer material, is separated from substrate 24 by a spacer 28. Spacer28 surrounds optoelectronic device 22 and serves as sidewalls for themodule. Transparent cover 26 generally is transparent to wavelengths oflight emitted by or detectable by optoelectronic device 22. Spacer 28preferably is composed of a non-transparent material, such as a vacuuminjected polymer material (e.g., epoxy, acrylate, polyurethane, orsilicone) containing a non-transparent filler (e.g., carbon black,pigment, or dye). Attached to one side of transparent cover 26 is anoptical element such as a lens 30. In the illustrated example of FIG.2A, lens 30 is formed by a replication technique and, together withoptoelectronic device 22, is present in an interior area 32 of module 20(i.e., on the sensor-side of the transparent cover). Sidewalls 34 oftransparent cover 26 also are covered by a non-transparent material 36,which in the illustrated example of FIG. 2A is composed of the samematerial as is used for spacer 28. The exterior surface of substrate 24includes one or more solder balls or other conductive contacts 38, whichcan be coupled electrically to optoelectronic device 22 by way ofconductive vias extending through substrate 24.

In the example of FIG. 2A, transparent cover 26 is substantiallyperpendicular to the module's optical axis and is substantially parallelto substrate 24. In some implementations, however, transparent cover 26can be tilted at an angle with respect to the plane of substrate 24.Examples are illustrated in FIGS. 2B, 2C and 2D. In each of theseexamples, sidewalls 34 of transparent cover 26 are covered by anon-transparent material 36, which may be composed, for example, of thesame material as is used for spacer 28. In the implementation of FIG.2C, spacer 28 also is tilted at an angle with respect to the plane ofsubstrate 24.

In some cases, the non-transparent material 36 that covers the sidewalls34 of transparent cover 26 is surrounded by another non-transparentmaterial (e.g., a PCB material 40 such as FR4, which is a gradedesignation assigned to glass-reinforced epoxy laminate material). Seemodule 20A in FIG. 2E. The glass-reinforced epoxy laminate material 40also can be substantially non-transparent to light emitted by ordetectable by optoelectronic device 22.

In some implementations, the module includes alignment features 42 thatextend beyond the object-side surface of the transparent cover 26 (seemodule 20B in FIG. 2F). Such alignment features 42 can facilitatepositioning of the module within a smartphone or other appliance. Thealignment features 42 can be composed, for example, of the same or adifferent non-transparent material as the spacer 28. They can beattached to the spacer 28 by a section of non-transparent material thatextends through the glass-reinforced epoxy laminate material 40.

Some implementations include a projection 44 that extends beyond the topof the transparent cover 26 at or near its side edges, as shown in themodule 20C of FIG. 2G. The projection 44, which can be composed of anon-transparent material (e.g., a polymer such as epoxy with carbonblack), can serve as a baffle to help guide light exiting or enteringthe module.

In some implementations, the optical element 30 is disposed on thesensor-side surface of the transparent cover 26. In otherimplementations, the optical element 30 (e.g., a lens or diffuser) isdisposed on the object-side surface of transparent cover 26 (see, e.g.,FIG. 2H) or optical elements can be disposed on both sides of thetransparent cover.

The following paragraphs describe various fabrication techniques formanufacturing the foregoing optoelectronic modules and other similarmodules that include a light emitting element (e.g., a LED, IR laser orVCSEL) or light detecting element (e.g., a photodiode) and an opticalelement such as a lens or diffuser integrated as part of the module.Some modules can include multiple optoelectronic devices (e.g., a lightemitting element and a light detecting element). In someimplementations, the modules are fabricated in a wafer-scale process sothat multiple modules (e.g., hundreds or even thousands) can bemanufactured at the same time. Some implementations include firstmounting or attaching a transparent wafer onto UV dicing tape, thendicing the transparent wafer into singulated transparent covers.Further, in some implementations a coating (e.g. an optical filter) maybe applied to a transparent wafer. The wafer subsequently can be mountedonto the UV dicing tape, and then diced into singulated transparentcovers. Some implementations include using a vacuum injection techniqueto form various elements on a structured substrate (i.e., a substratethat has a non-flat or non-planar surface). Various elements (e.g., theoptical elements or spacers) can be formed directly on one side or bothsides of the transparent wafer using one or more vacuum injection and/orreplication tools. Some implementations involve the placement ofsingulated transparent covers onto a support surface such as a carrierwafer, a vacuum chuck or UV dicing tape. The singulated transparentcovers can have various shapes (e.g., circular, quadratic).

FIGS. 3A-3E, for example, illustrate a wafer-level process forfabricating modules like the module 20 of FIG. 2A. A replication andvacuum injection tool 50 having optical element replication sections 58and spacer sections 60 is used to form a wafer-scale spacer/opticsstructure 72 that includes replicated optical elements 62 and vacuuminjected spacers 64 (see FIG. 3C). In particular, as shown in FIG. 3A,singulated transparent substrates 66, on which the optical elements(e.g., lenses) are to be formed, are placed on a support surface 68. Thesupport surface 68 can be implemented, for example, as a carrier waferwhich rests on polydimethylsiloxane (“PDMS”) vacuum sealing chuck 70.Alternatively, the vacuum sealing chuck 70 itself can serve as thesupport surface. In some implementations, the support surface 68 may beimplemented as a transient substrate (e.g., UV dicing tape, a PDMS,glass, polymer wafer, the tool(s) used to form the replicated opticalelements 62 and/or the spacers 64, or a combination of any of theforegoing examples). Singulated substrates 66 can be composed, forexample, of a transparent material such as glass or a transparentplastic or polymer material.

As used in this disclosure, replication refers to a technique in which astructured surface is embossed into a liquid, viscous or plasticallydeformable material, and then the material is hardened, e.g., by curingusing ultraviolet radiation or heating. In this way, a replica of thestructured surface is obtained. Suitable materials for replication are,for example, hardenable (e.g., curable) polymer materials or otherreplication materials, i.e. materials which are transformable in ahardening or solidification step (e.g., a curing step) from a liquid,viscous or plastically deformable state into a solid state. As shown,for example, in FIG. 3A, a replication material (e.g., a liquid, viscousor plastically deformable material) is placed onto the opticalreplication sections 58 of the replication tool 50 (FIG. 3A), and thereplication sections 58 are brought into contact with the singulatedtransparent substrates 66 so that the replication material is pressedbetween the upper surfaces of the singulated transparent substrates 66and the optical replication sections 58. The replication material thenis hardened (e.g., by UV or thermal curing) to form replicated opticalelements 62 (e.g., lenses) on the surface of the singulated transparentsubstrates 66.

Next, a vacuum injection material (e.g., a liquid, viscous orplastically deformable material) is injected through an inlet of thevacuum sealing chuck 70 so as to substantially fill spacer sections 60and form the spacer elements 64 (see FIG. 3B). At the same time, thespaces between the transparent substrates 66 are filled such that thesidewalls of the transparent substrates are covered by, or embeddedwithin, the vacuum injected material. In some implementations, a vacuumpump provided near an outlet of the vacuum sealing chuck 70 facilitatesthe vacuum injection material filling spacer sections 60. Although thereplication material that is used to form lenses 62 is transparent(i.e., to wavelengths of light that are emitted by or detectable by theoptoelectronic device), the vacuum injection material for the spacers 64preferably is non-transparent and can be composed, for example, of apolymer such as epoxy with carbon black. The vacuum injection materialfor the spacers 64 then is hardened (e.g., by UV or thermal curing),thus forming spacer elements 64 on the support surface 68 (FIG. 3B).Upon removal of the replication and vacuum injection tool 50, the resultis a wafer-scale spacer/optics structure 72 that includes opticalelements 62 on the transparent substrates 66, which are separatedlaterally from one another by portions of the spacer elements 64 (FIG.3C). Further details that may be applicable to the process of FIGS.3A-3B in some implementations are described in U.S. Provisional PatentApplication No. 61/746,347, the contents of which are incorporated hereby reference.

Next, spacer/optics structure 72 is attached to a PCB or other substrate74 on which are mounted multiple optoelectronic devices (e.g., lightemitting elements or light detecting elements) 76 (FIG. 3D). Theopposite surface of substrate 74 includes one or more solder balls orother conductive contacts 78, which can be coupled electrically tooptoelectronic devices 76 by way of conductive vias extending throughsubstrate 74. Substrate 74 is attached, for example, using a thermallystable adhesive, to spacer elements 64 on the spacer/optics structure72. The result is a stack 80 that includes an array of optoelectronicdevices 76, each of which is aligned with a respective one of theoptical elements (e.g., lenses) 62. In some cases, a non-transparentbaffle wafer is attached on the opposite side of the transparentsubstrates 66 so as to provide a baffle on the object-side of theresulting modules. In some implementations, image sensors may beattached or electrically connected to the PCB substrate, andsubsequently attached to the spacer optics structure 72 later in theprocess (e.g., after performance of the steps in FIG. 3D).

The stack 80 then can be separated along dicing lines 82 to formindividual flash modules 20 each of which includes an optoelectronicdevice aligned with a lens element attached to a transparent cover,whose exterior sidewalls are covered with, or embedded within,non-transparent material (see FIGS. 3E and 2A). Thus, the foregoingtechnique can be used to fabricate multiple modules 20 on a wafer-levelscale.

FIGS. 4A-4C illustrate steps in a wafer-level process for fabricatingoptoelectronic modules 21A as shown in FIG. 2B (i.e., having atransparent cover 26 tilted at an angle). Optical elements (e.g.,lenses) can be replicated, for example, on a transparent wafer (e.g.,composed of a glass or a transparent plastic or polymer material). Thewafer then can be separated (e.g., by dicing) into singulatedtransparent substrates 66, each of which includes a replicated opticalelement 62 on its surface. Next, as shown in FIG. 4A, the singulatedsubstrates 66 are placed on a first vacuum injection tool 51A, and asecond vacuum injection tool 51B is brought into contact above thesubstrates 66. The tools 51A, 51B include respective slanted surfaces63A, 63B between which the substrate 66 and optical element 62 arepositioned.

A vacuum injection material (e.g., a liquid, viscous or plasticallydeformable material) then can be injected so as to substantially fillspaces 60 and form the non-transparent spacer/sidewall elements 64 (seeFIG. 4B). As the spaces between the tools 51A, 51B are filled, thesidewalls of the transparent substrates 66 are covered by, or embeddedwithin, the vacuum injected material. In some implementations, a vacuumpump facilitates the vacuum injection material filling spaces 60. Thevacuum injection material preferably is non-transparent and can becomposed, for example, of a polymer such as epoxy with carbon black. Thelens yard of each singulated transparent substrate 66 should be chosensuch that it can protect the optical element 62 from the vacuum injectedmaterial (i.e., prevent the epoxy material from flooding the opticalelement). The vacuum injection material for the spacer/sidewall elements64 then is hardened (e.g., by UV or thermal curing). Upon removal of thevacuum injection tools 51A, 51B, the result is a wafer-scalespacer/optics structure 72A that includes optical elements 62 ontransparent substrates 66, which are separated laterally from oneanother by portions of the spacer/sidewall elements 64 (FIG. 4C).Subsequent processing of the wafer-scale spacer/optics structure 72A canproceed as described above in connection with FIG. 3D. After dicing,multiple modules 21 can be obtained, where each module includes a tiltedtransparent substrate on which there is an optical element. Side edgesof the module's transparent substrate are covered by non-transparentmaterial.

FIGS. 5A-5E illustrate steps in a wafer-level process for fabricatingoptoelectronic modules 21A as shown in FIG. 2C (i.e., having atransparent cover 26 tilted at an angle). As shown in FIG. 5A, a firstcombined replication and vacuum injection tool 51C is used to replicatean optical element (e.g., a lens) 62 on the (sensor-side) surface oftransparent singulated substrates 66. The first tool 51C includescavities 60A defined in part by slanted surfaces 61 at different heightsfrom one another.

While the first tool 51C remains in place, a second vacuum injectiontool 51D is brought into contact with the opposite (object-side) surfaceof the substrates 66 (see FIG. 5B). A vacuum injection material (e.g., aliquid, viscous or plastically deformable material) then can be injectedso as to substantially fill spaces between the tools 51C, 51D and formthe non-transparent spacer/sidewall elements 64A (see FIG. 5C). As thespaces between the tools 51C, 51D are filled, the sidewalls of thetransparent substrates 66 are covered by, or embedded within, the vacuuminjected material. Further, the spacer/sidewall elements 64A includeslanted end portions 65. After curing the vacuum injected material, thetools 51C, 51D are removed from the resulting optics/spacer structure,which then can be separated into individual optics/spacer components 73(see FIG. 5D). The optics/spacer components 73 then can be inverted andattached to a PCB or other substrate 74 that includes optoelectronicdevices (e.g., light emitting elements or light detecting elements) 76mounted on its surface (FIG. 5E). The optics/spacer components 73 aremounted such that the slanted end portions 65 are attached to thesurface of the substrate 74, which results in the spacer/sidewalls 28 ofeach component 73 being slanted at an angle with respect to thesubstrate 74. The resulting structure then can be separated (e.g., bydicing) into multiple modules 21A, as shown in FIG. 2C

FIGS. 6A-6C illustrate steps in a wafer-level process for fabricatingoptoelectronic modules 21B as shown in FIG. 2C (i.e., having atransparent cover 26 tilted at an angle). As shown in FIG. 5A,individual singulated transparent substrates 66 are supported on slantedsurfaces of a first combined replication and vacuum injection tool 51E.A second vacuum injection tool 51F is positioned above the singulatedsubstrates 66. The first tool 51E is used to replicate an opticalelement (e.g., a lens) 62 on the (sensor-side) surface of eachsingulated substrate 66. With both tools 51E, 51F in place, a vacuuminjection material (e.g., a liquid, viscous or plastically deformablematerial) is injected so as to substantially fill spaces between thetools and form the non-transparent spacer/sidewall elements 64B (seeFIG. 5C). As the spaces between the tools 51E, 51F are filled, thesidewalls of the transparent substrates 66 are covered by, or embeddedwithin, the vacuum injected material. After curing the vacuum injectedmaterial, the tools 51E, 51F are removed from the resultingoptics/spacer structure 72B that includes optical elements 62 ontransparent substrates 66, which are separated laterally from oneanother by portions of the spacer/sidewall elements 64 (see FIG. 6C).Subsequent processing of the wafer-scale spacer/optics structure 72B canproceed as described above in connection with FIG. 3D. After dicing,multiple modules 21B can be obtained, where each module includes atilted transparent substrate on which there is an optical element. Sideedges of the module's transparent substrate are covered bynon-transparent material.

FIGS. 7A-7E illustrate steps for fabricating optoelectronic modules 20Aas shown in FIG. 2E, in which the non-transparent material that coversthe sidewalls of the transparent cover is surrounded, for example, by aglass-reinforced epoxy laminate material (e.g., FR4). As shown in FIG.7A, singulated transparent substrates 66, on which the optical elementsare to be formed, are placed within respective openings (e.g., cavities)92 of a relatively sturdy non-transparent wafer 90, which can becomposed, for example, of a printed circuit board (PCB) material such asFR4. As described above, the singulated substrates 66 can be composed,for example, of a transparent material such as glass or a transparentplastic or polymer material. Each opening 92 preferably is slightlylarger than the diameter (or width) of the singulated transparentsubstrate 66 that is placed within the opening such that there is asmall gap 93 between the singulated transparent substrate 66 andadjacent portions of the non-transparent wafer 90. The non-transparentwafer 90 as well as the singulated transparent substrates 66 can beplaced on a PDMS vacuum sealing chuck 70, which serves as a supportsurface. In some cases, a separate carrier wafer, which is placed on thevacuum sealing chuck 70, serves as the support surface.

Next, replicated optical elements 62 (e.g., lenses) are formed on thesurface of the singulated transparent substrates 66 using a replicationand vacuum injection tool 50 (see FIG. 7B) in a manner similar to thetechnique described above in connection with FIGS. 3A-3B. In addition,non-transparent spacer elements 64 are formed by a vacuum injectiontechnique (see FIG. 7B) in a manner similar to the one described abovein connection with FIGS. 3A-3B. Gaps 93 between the singulatedtransparent substrate 66 and adjacent portions of the non-transparentwafer 90 also are filled with the vacuum injected spacer material. Thus,sidewalls of the transparent substrates 66 are covered by, or embeddedwithin, the vacuum injected spacer material (e.g., epoxy with carbonblack), which is surrounded by the material (e.g., FR4) of thenon-transparent wafer 90. The vacuum injected spacer material (e.g.,epoxy with carbon black) that is on the sidewalls of a particulartransparent substrate 66 thus forms a single contiguous region with aspacer element 64. Upon removal of the replication and vacuum injectiontool 50, the result is a wafer-scale spacer/optics structure 94 (FIG.7C).

Next, spacer/optics structure 94 is attached to a PCB or other substrate74 on which are mounted multiple optoelectronic devices 76 (FIG. 7D). Asdescribed in connection with the previous example, substrate 74 can beattached, for example, using a thermally stable adhesive, to spacerelements 64 on the spacer/optics structure 94. The result is a stack 96that includes an array of optoelectronic devices 76, each of which isaligned with a respective one of the optical elements (e.g., lenses) 62.In some cases, a non-transparent baffle wafer is attached on theopposite side of the transparent substrates 66 so as to provide a baffleon the object-side of the resulting modules.

The stack 96 then can be separated along dicing lines 82 to formindividual modules 20A each of which includes an optoelectronic devicealigned with an optical element attached to a transparent cover, whoseexterior sidewalls are covered with, or embedded within, a firstnon-transparent material (e.g., epoxy with carbon black) that issurrounded by a second non-transparent material (e.g., aglass-reinforced epoxy laminate material such as FR4). Thus, theforegoing technique can be used to fabricate multiple modules 20A on awafer-level scale (see FIGS. 7E and 2E).

FIGS. 8A-8D illustrate steps of another wafer-level process that, likethe previous process of FIGS. 7A-7E, also includes placing singulatedtransparent substrates for the optical elements within respectiveopenings (e.g., cavities) of a relatively sturdy non-transparent wafer.The process of FIGS. 8A-8D can be used to fabricate multipleoptoelectronic modules like the module 20D of FIG. 2H, in which theoptical element (e.g., lens) is disposed on the object-side surface ofthe transparent cover.

As shown in FIG. 8A, singulated transparent substrates 66 are placedwithin respective openings (e.g., cavities) 92 of a relatively sturdynon-transparent wafer 102, which can be composed, for example, of a PCBmaterial such as FR4. Here too, the singulated substrate 66 can becomposed, for example, of a transparent material such as glass or atransparent plastic or polymer material. Each opening 92 preferably isslightly larger than the diameter (or width) of the singulatedtransparent substrate 66 that is placed within the opening such thatthere is a small gap 93 between the singulated transparent substrate 66and adjacent portions of the non-transparent wafer 102. Thenon-transparent wafer 102 as well as the singulated transparentsubstrates 66 can be placed on a PDMS vacuum sealing chuck 70, whichserves as a support surface. In some cases, a separate carrier wafer,which is placed on the vacuum sealing chuck 70, serves as the supportsurface.

Next, a vacuum injection tool 100 having spacer sections 60 is used toform a wafer-scale spacer structure (see FIG. 8B). In particular, spacerelements 64 are formed by a vacuum injection technique that fills thespacer sections 60 with a non-transparent material. The vacuum injectionprocess can be similar to the one described above in connection withFIGS. 3A-3B. Gaps 93 between the singulated transparent substrate 66 andadjacent portions of the non-transparent wafer 102 also are filled withthe vacuum injected spacer material. Thus, sidewalls of the transparentsubstrates 66 are covered by, or embedded within, the vacuum injectedspacer material (e.g., epoxy with carbon black), which is surrounded bythe material (e.g., FR4) of the non-transparent wafer 102. Upon removalof the replication and vacuum injection tool 100, the result is awafer-scale spacer structure 104 that includes non-transparent spacers64 on a substantially planar supporting structure 101 that is composedof the transparent substrates 66, sections of the non-transparent wafer102, and portions of the non-transparent spacer material (e.g., epoxywith carbon black) on the sidewalls of the transparent substrates 66(see FIG. 8C). In contrast to the previous examples (i.e., FIGS. 3A-3Eand FIGS. 7A-7E), the optical elements (e.g., lenses) are not formed bythe same tool that is used to form the vacuum injected spacers 64.Instead, the optical elements are formed in a different process step.

As shown in FIG. 8C, spacer structure 104 can be attached to a PCB orother substrate 74 on which are mounted multiple optoelectronic devices76. As described in connection with the previous example, substrate 74can be attached, for example, using a thermally stable adhesive, tospacer elements 64 on the spacer structure 104. The result is a stack106 that includes an array of optoelectronic devices 76 surroundedlaterally by non-transparent spacers elements 64.

As also shown in FIG. 8C, a combined replication and vacuum injectiontool 108 is provided above the planar supporting structure 101 on theside opposite the spacer elements 64. Replication and vacuum injectiontool 108 includes optical element replication sections 110 for formingreplicated lens elements 111 on the object-side surface of thetransparent substrates 66. Replication and vacuum injection tool 108further includes baffle sections 112 and alignment sections 114 forforming, respectively, baffle and alignment features (e.g., features 42and 44 in FIG. 2H).

To form the replicated lens elements 111, a replication material (e.g.,a liquid, viscous or plastically deformable material) is placed onto theoptical replication sections 110 of the replication tool 108, and thereplication sections 110 are brought into contact with the singulatedtransparent substrates 66 so that the replication material is pressedbetween the upper surfaces of the singulated transparent substrates 66and the optical replication sections 110. The replication material thenis hardened (e.g., by UV or thermal curing) to form replicated lenses onthe object-side surface of the singulated transparent substrates 66.

In addition, a vacuum injection material (e.g., a liquid, viscous orplastically deformable material) is injected so as to substantially fillbaffle sections 112 and alignment sections 114 of the tool 108. Althoughthe replication material that is used to form the lenses 111 istransparent (at least to wavelengths of light that are to be emitted byor that are detectable by the optoelectronic device), the vacuuminjection material that fills the baffle sections 112 and alignmentsections 114 preferably is non-transparent and can be composed, forexample, of a polymer such as epoxy with carbon black. In general,however, using a first vacuum injection tool 100 to form the spacers 64and using a second vacuum injection tool 108 to form the baffle andalignment features allows the material that fills the baffle sections112 and alignment sections 114 to be the same as or different from thematerial that forms the spacer sections 64. The vacuum injectionmaterial for the baffle and alignment features then is hardened (e.g.,by UV or thermal curing). Upon removal of the replication and vacuuminjection tool 108, the result is a stack that includes optical elements(e.g., lenses), as well as baffle and alignment features, on itsexterior surface.

The stack then can be separated along dicing lines to form individualmodules 20D each of which includes an optoelectronic device aligned withan optical element attached to an object-side surface of the transparentcover, whose exterior sidewalls are covered with, or embedded within, afirst non-transparent material (e.g., epoxy with carbon black) that issurrounded by a second non-transparent material (e.g., aglass-reinforced epoxy laminate material such as FR4). Each module 20Dalso includes vacuum injected baffle features 44 and alignment features42 (see FIG. 8D). Thus, the foregoing technique can be used to fabricatemultiple optoelectronic modules 20D on a wafer-level scale.

As described above in connection with FIG. 8C, in some cases, a combinedreplication and vacuum injection tool 108 is used to replicate lenses onthe transparent substrates 66 and to form baffle features 44 andalignment features 42. In other implementations, instead of replicatingthe lenses directly on the transparent substrates 66, apreviously-formed optical stack including one or more optical elements(e.g., lenses) can be attached over each transparent substrate 66.

The foregoing example provides a module that includes an optical element(e.g., a lens) 30 on the object-side surface of the transparent cover26. The method described next in connection with FIGS. 9A-9D provides awafer-level technique for fabricating optoelectronic modules, like themodule 20C of FIG. 2G, that have an optical element (e.g., a lens) onthe surface of the transparent cover 26 facing the light emittingelement 22 (i.e., the sensor-side of the transparent cover). The methodof FIGS. 9A-9D also provides for vacuum injected baffle features andalignment features similar to those in the previous example.

As shown in FIG. 9A, singulated transparent substrates 66 for theoptical elements are placed within respective openings (e.g., cavities)92 of a relatively sturdy non-transparent wafer 120, which can becomposed, for example, of a PCB material such as FR4 or otherglass-reinforced epoxy laminate material. In this case too, each opening92 preferably is slightly larger than the diameter (or width) of thesingulated transparent substrate 66 that is placed within the opening.In addition to the openings 92 for the singulated transparent substrates66, the non-transparent wafer 120 has small vertical gaps 124 throughits width forming channels that are aligned with openings definingbaffle sections 126 and alignment sections 128 on the PDMS vacuumsealing chuck 122, which serves as a support surface.

Next, replicated optical elements 62 (e.g., lenses) are formed on thesurface of the singulated transparent substrates 66 using a combinedreplication and vacuum injection tool 100A (see FIG. B) in a mannersimilar to the technique described above in connection with FIGS. 3A-3B.In addition, non-transparent spacer elements 64 are formed by a vacuuminjection technique in a manner similar to the one described above inconnection with FIGS. 3A-3B. At the same time, gaps 124, as well asbaffle sections 126 and alignment sections 128 in the vacuum sealingchuck 122, also are filled with the vacuum injected spacer material(e.g., epoxy with carbon black). Thus, a single vacuum injection stepcan be used to form the spacer elements 64 on one side ofnon-transparent wafer 120, as well as baffle features 130 and alignmentfeatures 132 on the other side of non-transparent wafer 120. The sametool 100A can be used for both the vacuum injection of these features aswell as replication of the optical elements 62. The steps illustrated byFIGS. 9A-9B also result in sidewalls of the transparent substrates 66being covered by, or embedded within, the vacuum injected spacermaterial (e.g., epoxy with carbon black), which is surrounded by thematerial (e.g., FR4) of the non-transparent wafer 120. The vacuuminjected spacer material (e.g., epoxy with carbon black) that is on thesidewalls of a particular transparent substrate 66 thus forms a singlecontiguous region with a spacer element 64 and with a baffle feature 130and alignment feature 132. Upon removal of the replication and vacuuminjection tool 100A, the result is a wafer-scale spacer/optics structure134 (FIG. C).

Next, spacer/optics structure 134 is attached to a PCB or othersubstrate 74 on which are mounted multiple optoelectronic devices 76(see FIG. 9C). As described in connection with the previous example,substrate 74 can be attached, for example, using a thermally stableadhesive, to spacer elements 64 on the spacer/optics structure 134. Theresult is a stack 136 that includes an array of optoelectronic devices76, each of which is aligned with a respective one of the opticalelements (e.g., lenses) 62.

The stack 136 then can be separated along dicing lines to formindividual optoelectronic modules 20C each of which includes anoptoelectronic device aligned with an optical element attached to atransparent cover, whose exterior sidewalls are covered with, orembedded within, a first non-transparent material (e.g., epoxy withcarbon black) that is surrounded by a second non-transparent material(e.g., a glass-reinforced epoxy laminate material such as FR4). Thus,the foregoing technique can be used to fabricate multiple optoelectronicmodules 20C on a wafer-level scale (see FIGS. 9E and 2G).

In the illustrated examples of FIGS. 7A-7E and 9A-9D, optical elements(e.g., lenses) are provided only in the sensor-side of the modules.However, those processes can be modified to integrate formation ofoptical elements on the object-side of the modules as well. For example,after performing the steps illustrated by FIGS. 7A-7D, a second opticalelement (e.g., lens) 62A can be formed on the upper side of eachtransparent substrates 66 (see FIG. 10A). The second optical elements62A can be formed either prior to or after the PCB substrate 74 (withthe optoelectronic devices 76 mounted thereon) is attached to the spacerelements 64. Furthermore, the second optical elements 62A can be formed,for example, by a replication technique. The result is a stack 140 thatincludes an array of optoelectronic devices 76 each of which issurrounded laterally by a non-transparent spacer 64 and is aligned witha pair of optical elements 62, 62A, one on either surface of thetransparent substrates 66.

The stack 140 then can be separated along dicing lines to formindividual optoelectronic modules 20F (see FIG. 10B) each of whichincludes an optoelectronic device aligned with a pair of verticallystacked optical elements attached to the transparent cover, whoseexterior sidewalls are covered with, or embedded within, a firstnon-transparent material (e.g., epoxy with carbon black) that issurrounded by a second non-transparent material (e.g., aglass-reinforced epoxy laminate material such as FR4). Thus, theforegoing technique can be used to fabricate multiple optoelectronicmodules 20F on a wafer-level scale.

A second group of replicated optical elements (e.g., lenses) also can beprovided as part of the process of FIGS. 9A-9D. For example, afterperforming the steps illustrated by FIGS. 9A-9C, a second opticalelement (e.g., lens) 62A can be formed by replication on the upper sideof each transparent substrate 66 (see FIG. 11A). The second opticalelements 62A can be formed either prior to or after the PCB substrate 74(with the optoelectronic devices 76 mounted thereon) is attached to thespacer elements 64. The result is a stack 142 that includes an array ofoptoelectronic devices 76 each of which is surrounded laterally by anon-transparent spacer 64 and is aligned with a pair of optical elements62, 62A, one on either surface of the transparent substrate 66.

The stack 142 then can be separated along dicing lines to formindividual optoelectronic modules 20G (see FIG. 11B) each of whichincludes an optoelectronic device aligned with a pair of verticallystacked optical elements attached to the transparent cover, whoseexterior sidewalls are covered with, or embedded within, a firstnon-transparent material (e.g., epoxy with carbon black) that issurrounded by a second non-transparent material (e.g., aglass-reinforced epoxy laminate material such as FR4). In this example,each module 20G also includes baffle and alignment features 42, 44.Thus, the foregoing technique can be used to fabricate multipleoptoelectronic modules 20G on a wafer-level scale.

As described above in connection with the example of FIGS. 8A-8D, it ispossible to form the baffle and alignment features with anon-transparent material that is different from the material that formsthe spacers. FIGS. 12A-12E illustrate another example that allows thenon-transparent material for the baffle and alignment features to bedifferent from (or the same as) the material that forms the spacers.Using different materials may be desirable, for example, to allowvarious non-transparent parts of the modules to have differenttransparencies.

As shown in FIG. 12A, singulated transparent substrates 66 for theoptical elements are placed within respective openings (e.g., cavities)92 of a relatively sturdy non-transparent wafer 120, which can becomposed, for example, of a printed circuit board (PCB) material such asFR4 or other glass-reinforced epoxy laminate material. Each opening 92preferably is slightly larger than the diameter (or width) of thesingulated transparent substrate 66 that is placed within the opening.In addition to the openings 92 for the singulated transparent substrates66, the non-transparent wafer 120 has small vertical gaps 124 throughits width forming channels that are aligned with baffle sections 126 andalignment sections 128 on the PDMS vacuum sealing chuck 122, whichserves as a support surface.

Next, replicated optical elements 62 (e.g., lenses) are formed on thesurface of the singulated transparent substrates 66 using a combinedreplication and vacuum injection tool 100B (see FIG. 12B) that includesoptical element replication sections 58. Also, gaps 124, as well asbaffle sections 126 and alignment sections 128 in the vacuum sealingchuck 122, are filled with a non-transparent vacuum injected material(e.g., epoxy with carbon black) while the tool 100B remains in place.The same tool 100B thus can be used for both the vacuum injection ofthese features as well as replication of the optical elements 62. Thesteps illustrated by FIG. 12A result in sidewalls of the transparentsubstrates 66 being covered by, or embedded within, the non-transparentvacuum injected material (e.g., epoxy with carbon black), which issurrounded by the material (e.g., FR4) of the non-transparent wafer 120.The vacuum injected material (e.g., epoxy with carbon black) that is onthe sidewalls of a particular transparent substrate 66 thus forms asingle contiguous region with a baffle feature 130 and alignment feature132 (see FIG. 12B).

Next, the replication and vacuum injection tool 100B is removed, and asshown in FIG. 12B, a second vacuum injection tool 100C is provided toform the spacer elements 64. The second vacuum injection tool 100Cincludes spacer sections 60, which are filled by vacuum injection with anon-transparent material. As indicated above, the material for thespacers can be different from the material for the baffle and alignmentfeatures. After the spacer sections 60 are filled, the second vacuuminjection tool 100C is removed from the resulting spacer/opticsstructure 148 (see FIG. 12C).

One difference between the process of FIGS. 9A-9C and FIGS. 8A-8Crelates to the non-transparent material that fills the gaps 124 in thetransparent wafer 120. In FIGS. 8A-8C, the gaps 124 are filled at thesame time and with the same material as the spacer sections 60. On theother hand, in FIGS. 12A-12C, the gaps 124 are filled at the same timeand with the same material as the baffle and alignment sections 126,128. Thus, if different materials are used to form the spacers 64 andthe baffle/alignment features 130, 132, the material in the gaps 124will depend on the whether the process of FIGS. 8A-8C or the process ofFIGS. 12A-12C is used.

After removing the second tool 100C, spacer/optics structure 148 isattached to a printed circuit board (PCB) or other substrate 74 on whichare mounted multiple optoelectronic devices 76 (see FIG. 12C). Asdescribed in connection with previous examples, substrate 74 can beattached, for example, using a thermally stable adhesive, to spacerelements 64 on the spacer/optics structure 148. The result is a stack150 that includes an array of optoelectronic devices 76, each of whichis aligned with a respective one of the optical elements (e.g., lenses)62.

The stack 150 then can be separated along dicing lines to formindividual optoelectronic modules 20H each of which includes anoptoelectronic device aligned with an optical element attached to atransparent cover, whose exterior sidewalls are covered with, orembedded within, a first non-transparent material (e.g., epoxy withcarbon black) that is surrounded by a second non-transparent material(e.g., a glass-reinforced epoxy laminate material such as FR4). Thus,the foregoing technique can be used to fabricate multiple optoelectronicmodules 20H on a wafer-level scale.

A wafer-level process, similar in some respects to the processesdescribed above, can be used to fabricate modules that include both alight emitting element and a light detecting element. For example, asshown in FIG. 13A, singulated transparent substrates 66, on which theoptical elements are to be formed, are placed within respective openings(e.g., cavities) of a relatively sturdy non-transparent wafer 90A thatis on a PDMS vacuum chuck 70, which serves as a support surface.Replicated optical elements 62 (e.g., lenses) are formed on the surfaceof the singulated transparent substrates 66 using a combined replicationand vacuum injection tool 50A. In addition, non-transparent spacerelements 64A, 64B, 64C are formed by vacuum injection using the combinedreplication and vacuum injection tool 50A (see FIGS. 13A-13B). At thesame time, gaps 93 between the transparent substrates 66 and adjacentportions of the non-transparent wafer 90A are filled with thenon-transparent vacuum injected material so that the sidewalls of thetransparent substrates are covered by, or embedded within, thenon-transparent material. FIGS. 13A-13B are similar to FIGS. 7A-7B,except that the spacer sections 60A, 60B and 60C in the tool 50A cansizes that differ from one another. In particular, as will becomeevident from the description below, each narrower spacer section 60Bcorresponds to a spacer element 64B formed between adjacent opticalchannels for a single module. The wider spacer section 60C correspondsto the spacer element 64C forming the walls for two adjacent modules.Upon removal of the replication and vacuum injection tool 50A, theresult is a wafer-scale spacer/optics structure 94A that includesoptical elements 62 and spacer elements 64A, 64B, 64C (FIG. 13C).

Next, as shown in FIG. 13D, in some implementations, a second group ofoptical elements (e.g., lenses) 62A can be formed by replication on thesecond side each transparent substrate 66. Also, in someimplementations, a baffle wafer is attached on the opposite side of thetransparent substrates 66 so as to provide a baffle on the object-sideof the resulting modules. The spacer/optics structure 94A is attached toa PCB or other substrate 74 on which are mounted different types ofoptoelectronic devices 76A, 76B (e.g., light emitting elements 76A andlight detecting elements 76B). The light emitting and detecting elements76A, 76B alternate such that each light emitting element 76A is adjacenta light detecting element 76B. Alternatively, singulated light emittingand detecting devices can be attached to the spacer/optics structure94A. The resulting structure can be separated (e.g., by dicing) intomultiple modules 20I each of which includes adjacent optical channels,one of which includes a light emitting element 76A (e.g., a LED) and oneof which includes a light detecting element 76B (e.g., a photodiode).The adjacent optical channels are separated from one another by anon-transparent spacer 64. Furthermore, the sidewalls of the transparentcovers are embedded within a first non-transparent material (e.g., epoxywith carbon black) that is surrounded by a second non-transparentmaterial (e.g., a glass-reinforced epoxy laminate material such as FR4).Such modules can be used, for example, as proximity sensors.

In the foregoing examples, singulated transparent substrates 66 for theoptical elements (e.g., lenses) are placed within openings (e.g.,cavities) of a relatively sturdy non-transparent PCB wafer. In someimplementations, instead of inserting pre-formed singulated transparentsubstrates into openings in a non-transparent wafer, the PCB-type wafercan be pre-formed with transparent sections that correspond to thetransparent covers for the modules. For example, as shown in FIG. 14A, arelatively sturdy wafer 220, which can be composed, for example, of anon-transparent printed circuit board (PCB) material such as FR4 orother glass-reinforced epoxy laminate material, also includestransparent sections 266 that correspond to transparent covers for themodules. The wafer 220 has small vertical gaps 224 through its widthforming channels that are aligned with features 228 (e.g., alignment orbaffle sections) on the PDMS vacuum sealing chuck 222, which serves as asupport surface.

Next, replicated optical elements 262 (e.g., lenses) are formed on thesurface of the transparent sections 266 using a combined replication andvacuum injection tool 200. In addition, as indicated by FIGS. 14A-14B,spacer sections 260 in the tool 200 are filled with a non-transparentmaterial as described to form non-transparent spacer elements 264. Atthe same time, gaps 224, as well as alignment (and/or baffle) sections228 in the vacuum sealing chuck 222, also are filled with the vacuuminjected spacer material (e.g., epoxy with carbon black). Thus, a singlevacuum injection step can be used to form the spacer elements 264 on oneside of wafer 220, as well as alignment (and/or baffle) features 232 onthe other side of wafer 220. Furthermore, the same tool 200 can be usedfor both the vacuum injection of these features as well as replicationof the optical elements 262. As can be seen in FIGS. 14A-14B, the sidesof the transparent sections 266 remain covered by, or embedded within,surrounding non-transparent sections (e.g., FR4) of the wafer 220. Uponremoval of the replication and vacuum injection tool 200, the result isa wafer-scale spacer/optics structure 234 (FIG. 14C). In someimplementations, instead of forming the spacer elements 264 by vacuuminjection using the tool 200, the spacer elements 264 can be provided byattaching a spacer wafer to a structure that has the replicated lensesand the vacuum injected alignment (and/or baffle) features formedthereon.

Next, spacer/optics structure 234 is attached to a printed circuit board(PCB) or other substrate 74 on which are mounted multiple optoelectronicdevices 76 (see FIG. 14C). As described in connection with the previousexample, substrate 74 can be attached, for example, using a thermallystable adhesive, to spacer elements 64 on the spacer/optics structure234. The result is a stack 236 that includes an array of optoelectronicdevices 76, each of which is aligned with a respective one of theoptical elements (e.g., lenses) 262.

The stack 236 then can be separated along dicing lines to formindividual optoelectronic modules 20I (FIG. 14D) each of which includesan optoelectronic device aligned with an optical element attached to atransparent cover, whose exterior sidewalls are covered with, orembedded within, a non-transparent material (e.g., a glass-reinforcedepoxy laminate material such as FR4). Thus, the foregoing technique canbe used to fabricate multiple optoelectronic modules 20J on awafer-level scale.

In the foregoing examples, the fabrication methods include attaching aspacer/optics structure to a PCB or other substrate on which are mountedmultiple optoelectronic devices. In other implementations, singulatedoptoelectronic devices can be attached to the spacer/optics structureinstead of attaching a wafer-size substrate on which the optoelectronicdevices are mounted.

Furthermore, although some of the foregoing examples include a singleoptoelectronic device (e.g., light emitting or light detecting element)in each module, techniques similar to the foregoing techniques can beused to fabricate modules that include two or more light emittingelements, each of which is aligned with one or more respective opticalelements. Such modules, which can include non-transparent sidewallssurrounding two or more light emitting elements without a spacerseparating the light emitting elements from one another, can serve, forexample, as dual LED flash modules. In some implementations, the modulesalso may include other optoelectronic or optical components.

In some of the foregoing examples, during the fabrication process, eachsingulated transparent substrate 66 spans across the region for a singleoptical channel. However, in some implementations, it can beadvantageous to use somewhat larger singulated transparent substratesthat span, for example, across two optical channels. Using such widersingulated transparent substrates can, in some cases, increase stabilityduring fabrication. Also, the wider singulated transparent substratesmay be easier, in some instances, to position using pick-and-placeequipment. A process for fabricating optoelectronic modules usingsingulated transparent substrates that span multiple (e.g., two) opticalchannels is described below in connection with FIGS. 15A-15F. Each ofthe resulting modules can include, for example, two optoelectronicdevices (e.g., a light emitting device and a light detecting device).

FIGS. 15A-15E illustrate steps for forming passive optical elements(e.g., lenses) on transmissive substrates, as well as forming spacerfeatures, baffle features and wall features. As shown in FIG. 15A, thesefeatures can be formed using upper and lower PDMS tools 300A, 300B thatfacilitate formation of the passive optical elements by replicating themonto transmissive substrates, and formation of the spacer, baffle andwall features by a vacuum injection technique. The upper tool 300Aincludes replication features 302A that correspond to the passiveoptical elements (e.g., lenses) that are to be formed on the uppersurface of transmissive substrates. Likewise, the lower tool 300Bincludes replication features 302B that correspond to the passiveoptical elements (e.g., lenses) that are to be formed on the lowersurface of the transmissive substrates.

The upper and lower tools 300A, 300B also include respective spaces304A, 304B that correspond to regions for the wall features of themodules. Further, the lower tool 300B includes spaces 306 thatcorrespond to regions for the spacer features of the modules. The uppertool 100A includes spaces 308 that correspond to regions for the bafflefeatures of the modules.

To form the lens elements, a curable epoxy 310 is dispensed on thereplication features 302A of the upper tool 300A, as well as on thereplication features 302B of the lower tool 300B. See FIG. 15B. Also, asshown in FIG. 15C, a singulated transmissive substrate 312 is placedover each region of curable epoxy 310 on the lower tool 300A. Eachsingulated transmissive substrate 312 spans across two adjacent regionsof epoxy 310 that are separated by one of the spaces 306. As before, thesubstrates 312 can be composed, for example, of glass, sapphire or apolymer) that is transparent to the particular wavelength(s) ofinterest.

Next, as illustrated in FIG. 15D, the upper and lower tools 300A, 300Bare aligned with one another and brought into contact so that the epoxymaterial 310 on the replication features 302A of the upper tool 100Acomes into contact with the top surfaces of the respective transmissivesubstrates 312. The epoxy material 310 for the lenses then is hardened,for example, by UV or thermal curing. When subsequently cured, the epoxymaterial 310 should be transparent (at least to wavelengths of lightthat are to be emitted from or detected by the module).

Next, a non-transparent curable material is provided by vacuum injectionin the spaces 304A, 304B, 306, 308 between the tools 300A, 300B, suchthat the spaces are filled with the non-transparent material. Thenon-transparent material can be composed, for example, of a flowablepolymer material (e.g., epoxy, acrylate, polyurethane, or silicone)containing a non-transparent filler (e.g., carbon black, a pigment, aninorganic filler, or a dye). See FIG. 15E. The non-transparent materialsubsequently is hardened (e.g., by UV or thermal curing). The hardenednon-transparent material forms wall features 314, baffle features 318and spacer features 316. The tools 300A, 300B then can be removed. Theresulting structure 319 (comprising the transmissive substrates 312, thelenses 310, the spacer features 316, the baffle features 318 and thewall features 314) can be attached to a substrate wafer 320 on which aremounted optoelectronic devices (i.e., light emitting devices 76A andlight detecting devices 76B), as shown in FIG. 15F. The substrate wafer320 can be, for example, of a PCB wafer. The resulting stack 321 can beseparated (e.g., by dicing) along lines 322 into multiple modules, eachof which includes a light emitting device 76A and a light detectingdevice 76B in respective optical channels.

If dicing is performed as shown in FIG. 15F, the exterior sidewalls 326of the transparent covers 312 of the resulting modules will not becovered with a non-transparent material (see FIG. 16), which could allowlight leakage from the module and/or stray light into the module tooccur in some cases. A technique for providing a non-transparentmaterial over the exterior sidewalls of the modules is described belowin connection with FIGS. 15 and 16.

In some implementations, the structure 319 of FIG. 15F can be dicedprior to attachment to the substrate wafer 320. Also, in someimplementations, instead of attaching the structure 319 to a substratewafer 320 on which are mounted multiple light emitting and lightdetecting devices 76A, 76B, singulated optoelectronic devices 76A, 76Bcan be attached to the structure 319. The foregoing methods can enabletesting of the optical and/or optoelectronic components prior toassembly (i.e., prior to attachment of the support on which the devices76A, 76B are mounted to the structure 319).

The process of FIGS. 15A-15F, including the use of upper and bottomtools 300A, 300B, also can be employed for situations in which eachtransparent substrate spans across the region for only a single channel.

FIGS. 17A-17F illustrate another fabrication technique for obtaining astack similar to the stack 321 of FIG. 15F. In this case, as shown inFIG. 16A, multiple singulated transmissive substrates 312 are mounted ona sacrificial substrate 410. As before, the transmissive substrates 312can be composed, for example, of glass, sapphire or a polymer that istransparent to the wavelength(s) of interest (i.e., the wavelength(s) oflight emitted by the light emitting devices 76A and detectable by thelight detecting devices 76B). A combined replication and vacuuminjection tool 400A is provided, and a curable epoxy material isdispensed on the replication features 402 of the tool, which then isbrought into contact with the exposed surfaces of the transmissivesubstrates 312 to form replicated lens elements 310 as shown in FIG.17B. The epoxy material then is hardened, for example, by thermal or UVcuring. Also, spaces 404 between the tool 400A and the sacrificialsubstrate 410, as well as spaces 406 between the tool 400A and thetransmissive substrates 312, are filled with a non-transparent materialsuch as a flowable polymer material (e.g., epoxy, acrylate,polyurethane, or silicone) containing a non-transparent filler (e.g.,carbon black, a pigment, an inorganic filler, or a dye). See FIG. 17B.The non-transparent material subsequently can be hardened (e.g., by UVor thermal curing) to form wall features 416 and spacer features 418.The tool 400A and the sacrificial substrate 410 then are removed. Theresulting structure 420 ((comprising the transmissive substrates 312,the lenses 310, the spacer features 418 and the wall features 416) isillustrated in FIG. 17C.

The structure 420 then is mounted on a substrate wafer 320 (e.g., a PCBwafer) on which are mounted optoelectronic devices (i.e., light emittingdevices 76A and light detecting devices 76B), as shown in FIG. 17D. Asecond combined replication and vacuum injection tool 400B can be usedto form lenses on the second side of the transmissive substrates 312,baffle features and upper portion of the wall features 416. A curableepoxy material is dispensed on replication features 422 of the tool400B, which then is brought into contact with the exposed surfaces ofthe transmissive substrates 312 to form replicated lens elements 310B asshown in FIG. 17E. The epoxy material can be hardened, for example, bythermal or UV curing. Also, spaces 424 between the tool 400B and thepreviously-formed sections 416 of the wall features, as well as spaces426 between the tool 400B and the transmissive substrates 312, arefilled with a non-transparent material such as a flowable polymermaterial (e.g., epoxy, acrylate, polyurethane, or silicone) containing anon-transparent filler (e.g., carbon black, a pigment, an inorganicfiller, or a dye). See FIG. 15. The non-transparent materialsubsequently can be hardened (e.g., by UV or thermal curing) to form theupper sections 416B of wall features 416 and to form baffle features428. The second tool 400B then can be removed. The resulting structure421, which is illustrated in FIG. 17F, is similar to the structure 321of FIG. 15F obtained from the process of FIGS. 15A-15F. The structure412 of FIG. 17F also can be separated (e.g., by dicing) along lines 322into multiple modules, each of which includes a light emitting device76A and a light detecting device 76B in respective optical channels.

As noted above, if dicing is performed as shown in FIG. 15F or 14F, theexterior sidewalls 326 of the transparent covers 312 of the resultingmodules will not be covered with a transparent material (see, e.g., FIG.16), which could allow light leakage from the module and/or stray lightinto the module to occur in some cases. A technique for providingnon-transparent material to cover the sidewalls of the transparentcovers is now described.

One way in which the sidewalls 326 of the transmissive covers 312 can becovered with non-transparent material is illustrated by FIGS. 15A-15B.Starting, for example, with the structure 321 of FIG. 15F (or thestructure 421 of FIG. 17F), openings (e.g., trenches) 510 are formedfrom the top each baffle feature (e.g., 318) through the underlyingtransmissive substrates 312, as shown in FIG. 18A. The trenches 510should extend entirely through the thickness of the transmissivesubstrates 312 and, preferably, should extend partially into spacerfeatures (e.g., 316) below. The trenches 510 can be formed, for example,by dicing, micromachining or laser cutting techniques. The trenches 510subsequently can be filled with a non-transparent material 512 using,for example, a vacuum injection technique so as to provide anon-transparent layer on the side edges of the various portions of thetransmissive substrates 312. See FIG. 18B. The vacuum injectiontechnique can involve placing a PDMS tool on the top of the structureshown in FIG. 18A. The non-transparent material 510 covering the sideedges of the transmissive substrates 312 can be, for example, a curablepolymer material (e.g., epoxy, acrylate, polyurethane, or silicone)containing a non-transparent filler (e.g., carbon black, pigment, ordye). The structure 520 of FIG. 18B then can be separated (e.g., bydicing) into multiple individual modules.

For example, as illustrated in FIG. 19, the structure 520 can beseparated by dicing along lines 522 through the wall features 416, 416Bto form modules like the module 530 of FIG. 20. The module 530 includesa light emitting device 76A and a light detecting device 76B separatedfrom one another by a spacer 418 that serves as a non-transparentinterior wall. Non-transparent material 512 also separates thetransmissive substrates 312 form one another to help prevent stray lightfrom entering the optical detection channel. The exterior walls 416 ofthe module also are composed of non-transparent material and cover theexterior sidewalls 326 of the transmissive covers 312, which can helpprevent light leakage from the sides of the transmissive covers. Thestructure 321 of FIG. 15F can be processed in a similar manner to obtainmultiple modules similar to the module of FIG. 20.

In some implementations, instead of separating the structure 520 alongdicing lines 522 as in FIG. 19, the structure 520 can be separated alongdicing lines 524 passing through the non-transparent material 512 andthe spacers 418 (see FIG. 21) to form modules light modules like themodule 540 of FIG. 22. The module 540 also includes a light emittingdevice 76A and a light detecting device 76B separated from one anotherby an interior wall 416 that can help prevent stray light from enteringthe optical detection channel. The outer walls of the module arecomposed of non-transparent spacers 418 and non-transparent material 512that covers the exterior sidewalls 326 of the transmissive covers 312.The non-transparent material 512 can help prevent light leakage from thesides of the transmissive covers 312. The structure 321 of FIG. 15F canbe processed in a similar manner to obtain multiple modules similar tothe module of FIG. 22.

Although many of the foregoing examples include lenses as the opticalelements, some implementations may include other types of opticalelements (e.g., optical filters and/or FFL correction layers) inaddition to, or in place of, the lenses. In some cases, such opticalelements may be provided on a transparent substrate (e.g., wafer) priorto singulation. For example, in some cases, an optical filter layer or afocal length correction layer can be applied to a transparent coversubstrate (e.g., wafer), which then is diced into singulated covers eachof which has at least one of an optical filter or focal lengthcorrection layer on its surface. The focal length correction layer maybe, for example, a focal flange length (FFL) correction layer. The FFLsometimes is referred to as a flange focal distance. The singulatedcovers, each of which includes an optical filter layer or a focal lengthcorrection layer on its surface, then can be integrated into any of thefabrication techniques described above (e.g., FIGS. 3A-3E; FIGS. 4A-4C;FIGS. 5A-5E; FIGS. 6A-6C; FIGS. 7A-7E; FIGS. 8A-8D; FIGS. 9A-9D; FIGS.10A-10B; etc.).

Including a FFL correction layer can be particularly advantageous, forexample, for image sensor applications. Thus, in some instances, thetransparent cover may include a replicated lens on one side only or, insome cases, may not include a replicated lens on either side. An exampleis illustrated in FIGS. 23A and 23B, which show multi-channel modules500A and 500B, respectively.

Modules 500A and 500B of FIGS. 23A and 12B include an image sensor 522supported on a PCB or other substrate 524. Image sensor 522 hasoptically sensitive regions 523 that are surrounded laterally by aspacer 528, which also serves as sidewalls for the sensor-side of themodule. Side edges of the transparent covers 526 are laterallysurrounded and covered by the non-transparent material (e.g., an epoxywith carbon black). In some cases, the non-transparent materialsurrounding the transparent covers 526 is the same material as thespacers 228. Transparent covers 526 can be composed, for example, ofglass, sapphire or a polymer material, and are separated from imagesensor 522 by spacer 528. In the illustrated examples of FIGS. 23A and23B, the object-side of each transparent cover 526 includes an opticalfilter 530, which can be implemented, for example, as a thin coating.Likewise, the sensor-side of each transparent cover may include a FFLcorrection layer 532 to correct for the channel focal length. Thethickness of the FFL correction layer 532 in each channel may vary fromthe thickness of the FFL layer 532 in another channel. In some cases,only some of the channels have a FFL correction layer.

Non-transparent material 539 may extend beyond the top of transparentcovers 526 near their edges. Depending on the implementation,non-transparent material 536 that covers the sidewalls of thetransparent covers 526 can be the same as, or different from, thematerial of the spacer 528 and/or the non-transparent material 539 thatextends beyond the top of the transparent covers 526. The exterior sideof PCB substrate 524 can includes conductive contacts, which can becoupled electrically to image sensor 522 by way of conductive viasextending through substrate 524.

The modules 500A, 500B can include one or more optics assemblies 550.The optics assemblies can be attached to an assembly 540 that iscomposed of the transparent covers 526 (including a lens element, an FFLcorrection layer 532 or a filter layer 530, if present) andnon-transparent walls/spacers 528, 536, 539. Each optics assembly 550can include, for example, a stack of one or more injection moldedoptical elements (e.g., lenses) 552 placed in a lens barrel 554. In somecases, an array of injection molded lens stacks can be providedcollectively for more than one optical channel (see FIG. 23A), whereasin other implementations, a separate lens stack is provided for eachrespective channel (see FIG. 23B).

Multiple assemblies 540 including transparent covers 526 (together withthe FFL correction layer 532 and/or the filter layer 530) andnon-transparent walls/spacers 528, 536, 539 can be fabricated as part ofa wafer-level process. In some implementations, a channel FFL correctionlayer is provided on one side of a transparent wafer. The FFL correctionlayer may be composed, for example, of a glass or polymer material, andcan be applied, for example, by spin coating, spraying or sputtering. Anoptical filter layer may be applied to the other side of the transparentwafer. The spacers and walls for the modules can be formed using thetechniques described in detail above (e.g., replication or vacuuminjection, as well as trench formation and filling of the trenches withnon-transparent material in some cases). Transient substrates (e.g., UVdicing tape, a PDMS substrate, a glass substrate, a polymer wafer) canbe used to support the structure during the foregoing steps. In somecases, a lens may be replicated on the surface of the optical filterlayer. Further, if an optical filter layer is not provided on thetransparent wafer, then in some cases, a lens may be replicated directlyon the surface of the transparent wafer.

Next, optics assemblies (i.e., lens stacks) can be attached to theobject-side of the spacer/optics/embedded transparent cover assemblies.This can be accomplished either on a wafer-level scale or by attachingindividual lens stacks to the spacer/optics/embedded transparent coverassemblies. Next, the focal length (e.g., FFL) of each optical channelcan be measured and compared to a specified value. If the measured FFLfor particular channel deviates from a desired value, the FFL correctionlayer can be removed selectively in that channel to correct for the FFLvalue. Photolithographic techniques can be used, for example, topartially or entirely remove the FFL correction layer, as needed. Sincethe channels may have different FFL values, different amounts of thechannel FFL correction layer may be needed to achieve corrected FFLvalues for the various channels. For some channels, no FFL correctionmay be needed. In other cases, a portion of the channel FFL correctionlayer may be removed. In yet other cases, no portion of the channel FFLcorrection layer may be removed. Thus, depending on the implementation,the channel FFL correction layer may be present for all of the channelsor for only some of the channels. Furthermore, the thickness of thefinal channel FFL correction layer may vary from one channel to thenext, depending on the amount of FFL correction needed in each channel.

The wafer-level structure (including the spacers, transparent coverswhose side edges are surrounded and covered by non-transparent material,and optics assemblies) then can be separated into individual assemblies,each of which includes, for example, an array of optical channels. Eachof the separated assemblies then can be attached to an individual imagesensor assembly (i.e., a PCB substrate on which is mounted an imagersensor).

In some implementations, it may be desirable to provide an opticalfilter 530A directly on the active photosensitive regions 523 of theimage sensor 522. Such filters can be provided, for example, instead ofthe filters 530 on the transparent cover 526. This arrangement may beuseful, for example, where a lens is replicated on the surface of eachtransparent cover 526.

Each of the modules of FIGS. 23A and 23B includes multiple opticalchannels. Single modules that include similar features can be providedas well. As example of such a module 500C is illustrated in FIG. 23C.The sidewalls of the transparent cover 526 as well as the sidewalls ofthe optical filter 530 are covered by the non-transparent material ofthe spacer 228. The module 500C also includes an optics assemblyimplemented as a stack of one or more injection molded optical elements(e.g., lenses) 552 placed in a lens barrel 554. In the illustratedexample, the module 500C does not include an FFL correction layer 532.

The optical filters discussed above can be implemented in various ways.For example, in some implementations, a dielectric band-pass filter canbe applied to the photo sensitive surface of the light sensing element(e.g., an image sensor) or to a surface of the transparent cover that isdisposed over the light sensing element. In some cases, such a band-passfilter is deposited onto the transparent cover (or onto a transparentwafer in the case of a wafer-level process) by vapor deposition orsputtering. Preferably the dielectric filter is deposited onto atransparent cover composed, for example, of glass, sapphire or anothertransparent material that has mechanical/thermal-expansion propertiessimilar those of glass or sapphire. The band-pass filter can beadvantageous because it permits a very narrow range of wavelengths toimpinge on the light sensing element (e.g., a photodiode or imagesensor). A dielectric band-pass filter can, in some cases, permit highlyselective filtering. For example, a dielectric band-pass filter can beused to filter out ambient IR radiation while permitting thetransmission of a specific desired wavelength of IR (e.g., light beinggenerated from a projected light source).

In the foregoing fabrication examples, a spacer/optics structure (e.g.,72 in FIG. 3C) is attached directly by adhesive to a PCB or othersubstrate wafer on which are mounted multiple optoelectronic devices(e.g., light emitting elements or light detecting elements) (see, e.g.,FIG. 3D). In particular, the free ends of the spacer elements of thespacer/optics structure is attached directly by adhesive to the PCB orother substrate wafer. In the resulting modules, the spacer 28 thatseparates the PCB or other substrate 24 from the transparent cover 26 iscomposed of a non-transparent material, such as a vacuum injectedpolymer material (e.g., epoxy, acrylate, polyurethane, or silicone)containing a non-transparent filler (e.g., carbon black, pigment, ordye). See, e.g., FIGS. 2A-2H. In some implementations, however, insteadof attaching the spacer/optics structure directly to the PCB or othersubstrate wafer, the spacer/optics structure is attached to a structuralelement forming part of the substrate wafer. An example is illustratedin FIGS. 24A and 24B, which are discussed below.

As shown in FIG. 24A, a spacer/optics structure 602 includes transparentcovers 604 whose sidewalls 606 are covered by the same vacuum-injectednon-transparent material that forms the spacer 608. A substrate wafer618 comprises a metal frame 610 having openings and a molded cavity 614.The molded cavity 614 fits within the openings of the metal frame 610 sothat sidewalls of the metal frame 610 are encapsulated laterally by themolded cavity 614. The substrate wafer 618 (i.e., the combination of themetal frame 610 and molded cavity 614) also may be referred to as a“lead frame.” The metal frame 610, which may be composed for example ofa metal such as copper, aluminum or nickel, has optoelectronic devices612 mounted on its surface and spaced laterally form one another.Further, the molded cavity 614 should have dimensions that match thoseof the spacer 608 such that the free ends of the spacer elements 608 andmolded cavity 614 can be attached directly to one another by adhesive,as shown in FIG. 24B. This can be particularly advantageous, forexample, where the optoelectronic devices 612 are high-power lightemitters (e.g., a high power LED or VCSEL) because the material of themolded cavity 614 can be made relatively inexpensively and also can behighly reflective and resistant to high temperatures. The stack formedby the spacer/optics structure 602 and the substrate wafer 618 can beseparated along dicing lines 616 to form multiple modules, such as themodule in FIG. 25A. In some implementations, the substrate waferstructure 618 can be attached to any of the other types of spacer/opticsstructures discussed above to form other types of modules in which thenon-transparent spacer material covers the sidewalls of the transparentcover. Some examples are illustrated in FIGS. 25B-25F. Thus, in somecases the transparent cover 604 may include an optical element on one orboth of its surfaces. The optical element can be a lens (see FIGS. 25A,25B and 25C), an optical filter (see FIGS. 25D and 25E) or a FFLcorrection layer. In some cases, an optics assembly 550 including astack of lenses can be attached over the transparent cover 604 (seeFIGS. 25F and 25G).

In the modules of FIGS. 25A-25G, one end of the spacer 608 is attached(e.g., by adhesive) to an end of the molded cavity 614. Thus, the moldedcavity 614 is attached to the spacer 608, which may be composed, forexample, of a vacuum injected polymer material such as epoxy, acrylate,polyurethane, or silicone containing a non-transparent filler such ascarbon black, a pigment, or a dye. The sidewalls 606 of the transparentcover 604 in each module can be encapsulated laterally by the same orsimilar material as the spacer 608; likewise, the sidewalls of the metalsubstrate 610 in each module can be encapsulated laterally by the moldedcavity 614.

As used in this disclosure, the terms “transparent,” “non-transparent”and “transmissive” are made with reference to the particularwavelength(s) emitted by or detectable by the devices (e.g., 22A, 22B,76A, 76B) in the module. Thus, a particular feature, for example, may beconsidered “non-transparent” even though it may allow light of otherwavelengths to pass through.

Various modifications can be made within the spirit of the invention.Accordingly, other implementations are within the scope of the claims.

What is claimed is:
 1. A method of fabricating optoelectronic modulescomprising: disposing a plurality of transparent substrates betweenrespective slanted surfaces of first and second vacuum injection tools;injecting a vacuum injection material into spaces between adjacent onesof the transparent substrates while the transparent substrates aredisposed between the respective slanted surfaces of the first and secondvacuum injection tools; hardening the vacuum injection material to forma structure that includes the transparent substrates and the hardenedvacuum injection material; removing the first and second vacuuminjection tools from the structure; attaching the structure to amounting substrate on which are mounted a plurality of optoelectronicdevices, thereby forming a stack; and separating the stack into aplurality of modules each of which includes a respective one of thetransparent substrates disposed over a respective one of theoptoelectronic devices mounted on a respective portion of the mountingsubstrate, wherein side edges of the respective one of transparentsubstrates are covered by a portion of the hardened vacuum injectionmaterial, and wherein the respective one of the transparent substratesis slanted at an angle with respect to the respective portion of themounting substrate.
 2. The method of claim 1 wherein, when thetransparent substrates are disposed between the respective slantedsurfaces of the first and second vacuum injection tools, each of thetransparent substrates has a respective optical element thereon, theslanted surfaces of the first tool being in contact with the transparentsubstrates, and the slanted surfaces of the second tool being in contactwith the optical elements, and wherein each of the modules furtherincludes a respective one of the optical elements on the respectivetransparent substrate.
 3. The method of claim 2 wherein disposing aplurality of transparent substrates between respective slanted surfacesof first and second vacuum injection tools includes: placing each of thetransparent substrates on a respective one of the slanted surfaces ofthe first vacuum injection tool; and moving the second vacuum injectiontool such that each respective one of the slanted surfaces of the secondvacuum injection tool contacts a respective one of the optical elements.4. The method of claim 2 wherein the vacuum injection material includesa liquid, viscous or plastically deformable material.
 5. The method ofclaim 2 wherein the transparent substrates are transparent to one ormore particular wavelengths of light emitted by or detectable by theoptoelectronic devices, and wherein the vacuum injection material isnon-transparent to the one or more particular wavelengths.
 6. The methodof claim 1 wherein the transparent substrates are composed of a glass,plastic or polymer material.
 7. The method of claim 1 wherein, afterattaching the structure to a mounting substrate, part of the hardenedvacuum injection material serves as a spacer that separates thetransparent substrates from the mounting substrate.
 8. The method ofclaim 1 further including providing a respective optical element on eachof the transparent substrates before disposing the transparentsubstrates between the slanted surfaces of the first and second vacuuminjection tools.
 9. The method of claim 8 wherein providing a respectiveoptical element on each of the transparent substrates includes forminglenses by replication.
 10. The method of claim 1 wherein one of thefirst vacuum injection tool is used to replicate an optical element oneach of the transparent substrates.
 11. The method of claim 10 whereinthe vacuum injection material includes a liquid, viscous or plasticallydeformable material.
 12. The method of claim 10 wherein the transparentsubstrates are transparent to one or more particular wavelengths oflight emitted by or detectable by the optoelectronic devices, andwherein the vacuum injection material is non-transparent to the one ormore particular wavelengths.
 13. A method of fabricating optoelectronicmodules comprising: disposing a plurality of transparent substratesbetween respective surfaces of first and second tools, wherein eachrespective one of the transparent substrates is supported by arespective one of the surfaces of the first tool, and wherein the secondtool has a plurality of surfaces slanted with respect to a plane of thetransparent substrates; injecting a vacuum injection material intospaces between adjacent ones of the transparent substrates while thetransparent substrates are disposed between the respective surfaces ofthe first and second tools, the spaces being defined, in part, by thefirst and second slanted surfaces of the second tool, the vacuuminjected material covering side edges of the transparent substrates;hardening the vacuum injection material to form a structure thatincludes the transparent substrates and the hardened vacuum injectionmaterial; removing the first and second tools from the structure;separating the structure into a plurality of sub-structures each ofwhich includes a respective one of the transparent substrates andfurther includes slanted end portions defined by part of the hardenedvacuum injected material; attaching the slanted end portions of each ofthe sub-structures to a mounting substrate on which are mounted aplurality of optoelectronic devices; and separating the mountingsubstrate to form a plurality of modules each of which includes arespective one of the transparent substrates disposed over a respectiveone of the optoelectronic devices mounted on a respective portion of themounting substrate, wherein side edges of the respective one oftransparent substrates are covered by a portion of the hardened vacuuminjection material, and wherein the respective one of the transparentsubstrates is slanted at an angle with respect to the respective portionof the mounting substrate.
 14. The method of claim 13 further includingreplicating a respective optical element on each of the transparentsubstrates using the second tool.
 15. The method of claim 14 whereininjecting the vacuum injection material into the spaces between adjacentones of the transparent substrates is performed after replicating therespective optical element on each one of the transparent substrates,but before separating the first and second tools from one another. 16.The method of claim 13 wherein the plurality of slanted surfaces of thesecond tool include a first plurality of slanted surfaces and a secondplurality of slanted surfaces, wherein the first plurality of slantedsurfaces is at a distance from a plane of the transparent substratesthat is different from the second plurality of slanted surfaces.
 17. Themethod of claim 13 wherein after separating the structure into aplurality of sub-structures, the slanted end portions of each respectiveone of the sub-structures include a first slanted end portion at a firstdistance from a plane of the respective transparent substrate and asecond slanted end portion at a second distance from the plane of therespective transparent substrate, the second distance being differentfrom the first distance.
 18. The method of claim 13 wherein afterattaching the slanted end portions of each of the sub-structures to themounting substrate, the transparent substrates are titled at an anglewith respect to the plane of the mounting substrate.
 19. The method ofclaim 18 wherein after attaching the slanted end portions of each of thesub-structures to the mounting substrate, part of the hardened vacuuminjection material serves as spacers that separate the transparentsubstrates from the mounting substrate, the spacers being titled at anangle with respect to the plane of the mounting substrate.
 20. Themethod of claim 13 wherein disposing a plurality of transparentsubstrates between respective surfaces of first and second toolsincludes: placing each of the transparent substrates on a respective oneof the surfaces of the first tool; and moving the second tool so as toreplicate a respective optical element on each of the transparentsubstrates.